Fractal patterns in species distributions of some British scarce plants

By

Georges Herbert, CHEKUIMO TAGNE

P. O. Box 8047 Yaounde

Cameroon

Tel.: +237 761 5579

+237 220 8205

Email: azpa01@ureach.com

chekuimo@hotmail.com

Type of Presentation: the abstract is intended for a Poster.Name of Invited Symposium: Bi-annual Conference of International Society for Ecological Economics, from 01st - 14th July 2004, to be held in Montreal, Canada.

The theme of the 2004 meeting: "Challenging Boundaries: Economics, Ecology and

Governance"

Topic Area: Conservation issues concerning plants

Title: Fractal patterns in species distributions of some British scarce plants
Abstract: The analysis, measurement, and management of species abundance is central to ecology and conservation biology, but it has proved difficult to find a single index that adequately reflects the commonness or rarity of species across a range of spatial scales. The spatial distribution and fractal structure of two British scarce plants, Lobelia urens (heath lobelia) and Phyteuma orbiculare (round-headed rampion), have been examined at several different scales. The two species have similar degrees of local patchiness at scale coarser than 50 km and have contrasting coarse-scale between 50 km and 1 km scales, but differed consistently in the slopes of theirscale-occupancy curves distributions at scale finer than 1 km. The slope of thelog-log plot of L urens is not constant, but varies systematically with spatialscale, and from habitat to habitat at the same spatial scale. Abundance estimates suggest that the species P. orbiculare is found to be clumped at all scales, whereas L. urens is dispersed at intermediate scale. Fractal dimension analysis suggests that this changes through scale. The distribution varied in their pattern from highly clumped to randomly dispersed. Fairly predictions of L. urens can be made from 50 m and 200 m.

Abstract: The analysis, measurement, and management of species abundance is central to ecology and conservation biology, but it has proved difficult to find a single index that adequately reflects the commonness or rarity of species across a range of spatial scales. The spatial distribution and fractal structure of two British scarce plants, Lobelia urens (heath lobelia) and Phyteuma orbiculare (round-headed rampion), have been examined at several different scales. The two species have similar degrees of local patchiness at scale coarser than 50 km and have contrasting coarse-scale between 50 km and 1 km scales, but differed consistently in the slopes of theirscale-occupancy curves distributions at scale finer than 1 km. The slope of thelog-log plot of L urensis not constant, but varies systematically with spatialscale, and from habitat to habitat at the same spatial scale. Abundance estimates suggest that the species P. orbiculare is found to be clumped at all scales, whereas L. urens is dispersed at intermediate scale. Fractal dimension analysis suggests that this changes through scale. The distribution varied in their pattern from highly clumped to randomly dispersed. Fairly predictions of L. urens can be made from 50 m and 200 m.

Fractal dimension, Conservation issues, conservation schemes

Chair own and Name of Contact: CHEKUIMO TAGNE Georges Herbert, P. O. Box 8047 Yaounde-Cameroon (chekuimo@hotmail.com)Table:
Fractal dimension (Db) of the two focal species